1. Field of the Invention
The present invention generally relates to the field of telecommunications. More specifically, the invention is directed to a method and apparatus for providing a network-based presence in an H.323-based communications system to handle one or more incoming calls and to provide various services in instances where the called parties are unavailable.
2. Description of the Related Art
H.323 is an International Telecommunications Union (ITU) standard that provides guidelines for terminals and equipment that provide multimedia communications services over packet-based computer networks (PBNs). H.323 terminals and equipment may carry real-time audio, video and/or data.
The packet based network over which H.323 terminals communicate may be a point-to-point connection, a single network segment, or an inter-network having, multiple segments with complex topologies, such as local area networks (LANs), Intra-Networks, and Inter-Networks, including the Internet.
H.323 terminals may be used in point-to-point, multi-point, or broadcast configurations (as described in H.332). They may interwork with H.310 terminals on B-ISDN, H.320 terminals on N-ISDN, H.321 terminals on B-ISDN, H.322 terminals on Guaranteed Quality of Service LANs, H.324 terminals on GSTN and wireless networks, V.70 terminals on GSTN, and voice terminals on GSTN or ISDN through the use of Gateways. H.323 terminals may be integrated into personal computers or implemented in stand-alone devices such as video telephones.
Computer networks which are capable of transmitting data or information between locations, such as the above-mentioned Internet, have been used to transmit audio information between computers without incorporating H.323-based communications systems. At the transmitting computer, a person's voice may be digitized using a conventional analog to digital (A/D) converter and transmitted to the receiving location where it is passed through a conventional digital to analog (D/A) converter and presented as audio. This type of audio connectivity is somewhat similar to flat rate telephony, in that audio information may be transmitted from one location to another by way of a high bandwidth, flat rate communications medium.
This type of computer telephony system suffers from several major disadvantages. First, the system is limited to only those people who have access to the Internet and who are using compatible end-point software. In addition, while Internet access has now widely proliferated, it has not reached the near universal accessibility of traditional telephone service over public switched telephone networks (PSTNs) and the like. Thus, such a computer telephony system is totally useless if a user on the Internet desires to communicate with someone who does not have access to the Internet.
On the other hand, an H.323-based communications system allows people on a computer network, such as the Internet, to communicate with people on a conventional telephone network, such as a PSTN, general switched telephone network (GSTN), integrated services digital network (ISDN), or other switched circuit network (SCN). Such a system provides the appropriate translation between SCN and PBN data formats and between different communication procedures, in order to allow a user on one system (such as the PSTN) to communicate with a user on an otherwise incompatible system (such as a packet based network).
While H.323-based communications systems effectively support communication between two otherwise incompatible networks, current use of those systems has been somewhat limited. Current systems are designed to support communication between two parties, and also provide for conferencing of multiple parties in a single call. However, H.323-based systems do not presently address the provision of more traditional phone behavior offered in PSTN and other conventional telecommunications networks. This is a significant drawback, especially for those who are already reluctant to convert from conventional telecommunications networks to an H.323-based system for their telecommunications needs.
As an example, one shortcoming associated with current H.323-based communications systems is that there is no procedure for connecting an incoming call with a network-based service such as voicemail when a called party's terminal is off-line. Existing H.323 systems provide services such as call forwarding and voice mail; however, these services are implemented solely at the terminal end-point being called. Thus, if the party's terminal is off-line, these services are simply unavailable, and the call cannot be completed.
Accordingly, there continues to be a need for a communications system that provides for communication between a packet based network (PBN) and a conventional switched circuit network (SCN), while simultaneously providing various services for handling an incoming call in the event the called party is unavailable, whether or not that party's terminal is on-line. The present invention addresses these needs and others.